The invention relates to a hydraulic automotive brake system with wheel slip control, with a pressure medium source onto which a main pressure line is connected, which leads to a wheel brake, with a pressure relief line that connects to the wheel brake and to a supply reservoir, and in which a pressure modulation valve is arranged that either separates the supply reservoir from the wheel brake or connects it to the wheel brake, as well as with a control orifice valve arranged in the main pressure line upstream of the pressure relief line, actuated by a change in the hydraulic pressure.
A brake system of the above indicated type has become known from DE 43 19 227 A1, with a pressure medium source to which a main pressure line is connected, leading to a wheel brake. In turn, the wheel brake has a connection for a pressure relief line which leads to a low pressure reservoir through an electromagnetically actuated outlet valve. A hydraulic pump is connected downstream of the low pressure reservoir, leading the pressure medium of the low pressure reservoir back to the main pressure line, which is connected to a brake pressure transducer. The brake pressure transducer as well as the hydraulic pump are to be regarded as pressure medium sources to supply the wheel brakes. An electromagnetically actuated inlet valve is located in the main pressure line, between the connection of the auxiliary pressure pump to the main pressure line and the connection of the outlet valve to the main pressure line, with an orifice control valve following downstream of the inlet valve in the main pressure line. This orifice control valve is hydraulically actuated interdependent with the pressure difference before and after the inlet valve. The orifice control operation is hereby subject to the influence of the dynamic pressure drop inside the inlet valve. Correspondingly, to operate this orifice control valve, a relatively high switching pressure is required, the lowering of which would prove to be expedient.
Therefore, the object of the present invention is to fundamentally improve a hydraulic automotive brake system with wheel slip control of the generic type, such that a control orifice operation can be created that is simple to realize with as little medium use as possible, said operation, moreover, being characterized by the most simple, rapid and operationally reliable mode of operation.